Description: (Applicant's Description) Cutaneous malignancies represent the most common type of cancer in the United States. Understanding the biological basis of such cancers, leading to the development of improved therapies, is a major ongoing goal of the Cutaneous Oncology Program, which includes 23 investigators representing 10 departments and three off-site members. The Program includes basic scientists and clinicians with a common interest in understanding the biology of cutaneous neoplasms. One of the major long-term goals of the Cutaneous Oncology Program is to link the clinical activities in malignant melanoma, cutaneous T-cell lymphoma, and non-melanoma skin cancers with laboratory-based efforts aimed at prevention, improved diagnosis, and treatment of these diseases. The program has access to two large databases of patients with malignant melanoma and cutaneous T-cell lymphoma to assist in the examination of novel molecular determinants of tumor progression. Currently funded research undertaken by program members includes: molecular basis of basal cell nevus syndrome and xeroderma pigmentosum; calcium and keratinocyte differentiation; proteases and progression of squamous cell carcinoma; and multi-step cutaneous carcinogenesis in transgenic mice. Current cancer prevention and control efforts focus on understanding the biology of melanoma in women and improving the diagnostic skills of primary care physicians in the realm of non-melanoma skin cancers.